

.pos_fiex{
    position: fixed;
    left: 0;
    right: 0;
    bottom: 0;
    height: 3rem;
    line-height: 3rem;
    color: #fff;
    background: #4DB1EF;
    text-align: center;
    font-size: 1.2rem;
    display: flex;
    display: -webkit-flex;
    -webkit-align-items: center;
    -webkit-justify-content: center;
    align-items: center;
    justify-content: center;

}

.buttom_bac{
    color: #fff;
    background: #4DB1EF;
    width: 100%;
    height: 4rem;
    font-size: 1.2rem;
    font-weight: bold;
}
.body_bac{
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
}